Urinary tract infection in young children (UTIs)

infection; kidney; urine; bladder; ureter; urethra; wee; ;

The urinary tract means the bladder and kidneys, and the tubes running between them, and the tube from the bladder out of the body.

Urinary tract infections (UTIs) are fairly common in children. About 2% of boys and 8% of girls will have a urinary infection during their childhood. If infections happen often, they can cause damage to the kidneys.

For some children it is easy to know that the infection is in the urinary tract, but for others, especially babies, the reason for being unwell may be more difficult to work out. In this topic the medical terms will be used, with an explanation, so you can understand the words that your doctor uses.

Important noteIf your child has any of the following you should get medical advice:

your child seems unwell

blood in the urine (wee)

starting to do wee very often when this is not the child's usual pattern

pain when doing wee

starting to wet pants during the day when the child has previously been dry

The urinary tract is made up of the kidneys, the tubes (ureters) leading from the kidneys to the bladder, the bladder itself and the tube leading from the bladder to the outside of the body (the urethra).

The kidneys act as 'cleaners' of the blood. They separate out 'waste' from the blood and then get rid of the waste by making urine (wee). Urine is mostly water, but it also contains many different chemicals that the body needs to get rid of.

The bladder wall has many muscles, some of which (those around the bottom or 'neck' of the bladder) hold onto the urine until the person is ready to let it out (urinate, wee), and other muscles which squeeze the urine out when you go to the toilet. Babies do not have conscious control of any of these muscles, but as they get older they get some control of the muscles which hold on to the urine so that they can be 'toilet trained'.

Urine infections are usually caused when bacteria (germs) get into the bladder or urethra.

The bacteria which cause most of the infections are ones from the bowel (gut), and it appears that these germs go from the skin outside through the urethra up into the bladder. Normally, passing urine 'washes' any bacteria out of the urethra, but for some children this does not seem to work.

The infection sometimes is only in the bladder (cystitis) and urethra, but it can also spread back up the ureters to the kidney.

If a child has several urinary tract infections, often there is something that is not normal about the way the bladder and the other tubes are formed. This can mean that the bladder does not empty properly when the child passes urine and the urine which stays in the bladder can provide 'food' for bacteria to grow in.

One common reason why urine stays in the bladder is that the tubes from the kidney to the bladder (the ureters) may not close off when urine is being squeezed out of the bladder (when your child is doing wee), so that as well as the urine going down the urethra to the outside, some goes back up the ureters towards the kidneys. This is called vesico-ureteric reflux ('vesico' meaning the bladder, and 'ureteric' meaning the ureters from the kidney to the bladder, 'reflux' means going back again).

In young babies urine infections are more common in boys than girls, but in toddlers and older children, girls are more likely to have the infections.

It is possible that girls have more infections because the urethra of a girl is shorter (so it is easier for germs to get up into the bladder) and the opening of the urethra is closer to the anus (opening of the bowel) where the germs that cause these infections usually come from.

Parents are often advised to wipe their baby girl's bottom from the front to the back so that germs from the bowel are not spread to the opening of the urethra. This is likely to be helpful but it has not been proved for sure that it is helpful. It will not prevent infections if there are other problems such as reflux.

Uncircumcised boy babies seem a little more likely to get urine infections because germs may grow under the foreskin in drops of urine, but infections that are caused by this are rare and most doctors will not advise circumcision for this reason alone. (About 1000 newborn boys would need to be circumcised to protect 10 boys from infection, and it is not possible to tell which boys would benefit from circumcision. Sometimes circumcision is done at an older age if an uncircumcised boy gets several urine infections.)

Infections of the urinary tract can show themselves in many different ways.

In young babies, often the signs are rather vague. The baby may be more irritable than usual and not be able to feed as well. The baby may have a fever, but often not a high fever. Often the baby just seems a 'bit unwell'.

Older babies may seem unwell, have a fever, be off their food, vomit, have diarrhoea and sometimes a nappy rash.

Preschool children may have some or all of these signs and may also have tummy pain, and more of the signs that older children and adults, have such as needing to go to the toilet very often and urgently, and pain when passing urine. Their urine may smell stronger and look dark.

Some children start to wet their beds again, after having been dry at night.

Some children may wet their pants during the day because they cannot get to the toilet quickly enough.

Sometimes a urine infection is found when a child seems unwell, but there is no obvious cause for being unwell.

Frequent UTIs can damage the kidney and may eventually cause renal failure (the kidney can no longer remove waste products from the blood). People with renal failure may need dialysis (a machine cleans their blood) or kidney transplant.

Having a few infections is not enough to cause renal failure, but it is important to find our why the infection happened, because if there is a physical problem with the kidney, bladder or the tubes connecting them, treatment may prevent future infections, and possible renal failure.

If it seems that a baby or child may have a urine infection, the urine will need to be examined under a microscope and also a 'culture' done. A culture is where the germ (bacteria) is grown in special gel. By looking at this it is possible to tell what the germ is and which antibiotics will kill it. This may take a day or so, and the doctor may not be able to start treatment straight away, until the result of this test is known.

Another way is to dip "Test strips" in the urine (wee) and these may show that a urine infection is likely to be present. However these are usually not enough to be sure, unless the child has had infections before. The test strip result can be normal even if a child has an infection.

Collecting clean urine for this test from young children can be difficult and a special bag may be used. Sometimes the urine is collected in other ways (such a using a catheter (tube) passed up the urethra into the bladder).

If it is shown that there is a urine infection, usually more tests will be done to see if the bladder, ureters, urethra and kidneys are normal. Usually the first test done will be an ultrasound (similar to the ultrasound done to check unborn babies.)

Most children with urinary tract infections will need antibiotics. These may be given by mouth if the child is not too unwell, but sometimes they need to be given by injection.

If the child is having many infections and there is a problem with how the urinary tract is formed, an operation may be recommended. Before this is done the baby or child is likely to be given a low dose of antibiotics (usually once a day) to prevent further infections.

Having a urinary tract infection is painful. The urine becomes acidic and causes a burning pain when the child passes urine, and there can be pain in the lower abdomen and a feeling of needing to pass urine often. It may be useful to give the child medication which neutralises the acid (an alkaliniser). Several types are available at pharmacies. Check with the pharmacist about whether one is suitable for a child.

The information on this site should not be used as an alternative to professional care. If you have a particular problem, see a doctor, or ring the Parent Helpline on 1300 364 100 (local call cost from anywhere in South Australia).

This topic may use 'he' and 'she' in turn - please change to suit your child's sex.